Construction machinery may use a hydraulic fluid to drive actuators such as a boom, a cylinder, a bucket, a travelling motor, a swing motor, etc. In the large construction machinery, at least three main hydraulic pumps may be used to discharge more hydraulic fluid, thereby obtaining a much more driving power.
Especially, a separate main hydraulic pump may be provided only for a swing operation. Alternatively, a hydraulic fluid discharged from one main hydraulic pump may be distributed to different actuators to perform a multiple swing operation, for example, the swing operation and another operation together.